/*
 * Copyright (c) 2022, Peter Abeles. All Rights Reserved.
 *
 * This file is part of Efficient Java Matrix Library (EJML).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.ejml.dense.row;

import org.ejml.data.DMatrixD1;

import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;

/**
 * Renders a matrix as an image. Positive elements are shades of red, negative shades of blue, 0 is black.
 *
 * @author Peter Abeles
 */
public class DMatrixComponent extends JPanel {
    BufferedImage image;

    public DMatrixComponent( int width, int height ) {
        image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        setPreferredSize(new Dimension(width, height));
        setMinimumSize(new Dimension(width, height));
    }

    public synchronized void setMatrix( DMatrixD1 A ) {
        double maxValue = CommonOps_DDRM.elementMaxAbs(A);
        renderMatrix(A, image, maxValue);
        repaint();
    }

    public static void renderMatrix( DMatrixD1 M, BufferedImage image, double maxValue ) {
        int w = image.getWidth();
        int h = image.getHeight();

        double widthStep = (double)M.numCols/image.getWidth();
        double heightStep = (double)M.numRows/image.getHeight();

        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                double value = M.get((int)(i*heightStep), (int)(j*widthStep));

                if (value == 0) {
                    image.setRGB(j, i, 255 << 24);
                } else if (value > 0) {
                    int p = 255 - (int)(255.0*(value/maxValue));
                    int rgb = 255 << 24 | 255 << 16 | p << 8 | p;

                    image.setRGB(j, i, rgb);
                } else {
                    int p = 255 + (int)(255.0*(value/maxValue));
                    int rgb = 255 << 24 | p << 16 | p << 8 | 255;

                    image.setRGB(j, i, rgb);
                }
            }
        }
    }

    @Override
    public synchronized void paint( Graphics g ) {
        g.drawImage(image, 0, 0, this);
    }
}
